This invention relates to a method and apparatus for space dyeing yarn to obtain substantially random variations of dye along the length of yarn strands, and more particularly to a method and apparatus of applying dyes of different colors to moving yarn strands while varying the amount of each dye color applied to the yarn so that the length of each dye color or dye spot on the yarn and the location of the dye spots may be varied in accordance with selective substantially random patterns.
It is desirable and known to provide yarns which have a color pattern that varies along the length of the yarn strand. Such yarns, known as space dyed yarns, find utility in certain carpet having a multi-color effect. Ideally, the carpet has no visible pattern. However, the space dyeing apparatus of the prior art does not permit random pattern repeats, but repeats of finite lengths. Thus, when the yarn is tufted into a backing to form carpet, a chevron pattern, known as the moire-effect, seen as curved lines across the finished product may result.
In Haselwander U.S. Pat. Nos. 5,339,658; 5,386,606 and 5,386,712, the known prior art space dyeing systems are discussed and a system is disclosed wherein yarn strands are fed over support members above a series of dye applicator rolls rotatably disposed within respective dye pans, and a pattern roll is disposed above and offset from the respective applicator rolls, each pattern roll carrying a circumferential array of paddles which may be selectively positioned about the circumference to engage and deflect the yarn strands against the respective applicator rolls. All of the dye applicator rolls are driven by a first drive at a first speed, and all of the pattern rolls are driven by a second drive at a second speed. Although apparatus constructed in accordance with the teachings of the Haselwander patents provide good results, it has pattern repeat limitations. That is, the maximum length of a pattern repeat is limited. With apparatus having pattern rolls spaced apart at five inch centers, and a roll circumference of approximately one foot, the maximum pattern repeat is in the order of approximately 150 inches. After drying, this pattern repeat shrinks to approximately 137 inches. In another known space dyeing system, disks having a slotted sector are rotated above the moving yarn strands and a nozzle corresponding to each disk and spraying a dye of a different respective color onto the disk is provided, the dye pattern being dependent upon the size of the sector opening.
In each of these prior art situations, the relatively short pattern repeat may be unacceptable to the carpet stylist or designer for certain carpet stylings. Additionally, with such short pattern repeats, adjoining yarns may line up causing the undesirable chevron effect. Another limitation of the prior art is the lack of flexibility in producing different length dye spots. For example, since the pattern rolls, and apparently the rotating disks, are driven at fixed, albeit adjustable, speeds, the length of a dye spot of a particular color, i.e., the length of a particular color dye on the yarn, is fixed, and its location in the pattern repeat is also fixed. As aforesaid, such deficiencies of the prior art apparatus and methods present limitations to the carpet styles producable with such yarns.